1. Field of the Invention
The present invention relates to multilayer ceramic capacitors.
2. Description of the Related Art
Multilayer ceramic electronic components such as multilayer ceramic capacitors and the like have been used in a variety of electronic apparatuses. A multilayer ceramic capacitor generally includes a ceramic multilayer body in which a first inner electrode and a second inner electrode are disposed with a ceramic dielectric layer interposed therebetween, and outer electrodes that are formed on both end portions of the ceramic multilayer body.
In recent years, the severity of the environments in which multilayer ceramic capacitors are used has significantly increased. For example, multilayer ceramic capacitors that are used in mobile apparatuses such as cellular phones, portable audio players, and the like are required to withstand the shock of a fall. To be specific, it is necessary to prevent a multilayer ceramic capacitor from falling off of the mounting substrate even if the multilayer ceramic capacitor receives the shock of a fall. Further, it is necessary to prevent the generation of cracks in the multilayer ceramic capacitor.
In addition, multilayer ceramic capacitors used in on-vehicle devices such as an ECU (electronic control unit) and the like are required to be heat-resistant. To be specific, it is necessary to prevent the generation of cracks in a multilayer ceramic capacitor even if a flexural stress is generated due to thermal shrinkage or thermal expansion of the mounting substrate or a tensile stress applied to a first outer electrode and a second outer electrode of the multilayer ceramic capacitor. When the above-mentioned flexural stress and/or tensile stress exceeds the strength of the ceramic multilayer body, a crack is generated in the ceramic multilayer body.
As such, Japanese Unexamined Patent Application Publication No. 11-162771 discloses a technique in which, by using a conductive epoxy-based thermosetting resin containing metal powder for outer electrodes of a multilayer ceramic capacitor, a stress received from the substrate is somewhat alleviated so that the generation of a crack in a ceramic multilayer body is reduced even in a severe environment.
However, when, like in Japanese Unexamined Patent Application Publication No. 11-162771, an outer electrode has a structure in which a conductive epoxy-based thermosetting resin layer, a nickel plating layer, and a tin-based plating layer are formed in that order on a baking electrode layer as a base electrode layer, there arises a problem in that equivalent series resistance (ESR) becomes excessively high due to the presence of the epoxy-based thermosetting resin layer with excessively high resistivity, although it is a conductive material, in comparison with a regular outer electrode that does not include a conductive resin layer.